CVE-2026-86115
Received Received - Intake

SSRF Bypass via Path Manipulation in Sim

Publication date: 2026-09-05

Last updated on: 2026-09-05

Assigner: VulnCheck

Description
Sim before 0.8.14 classifies tool requests as internal based on URL prefix matching without scheme normalization, skipping SSRF validation and minting internal authentication tokens. Authenticated workflow authors can bypass external URL validation by supplying paths starting with /api/ in HTTP blocks to reach internal-only endpoints like POST /api/function/execute.

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Meta Information

Published
2026-09-05
Last Modified
2026-09-05
Generated
2026-09-05
AI Q&A
2026-09-05
EPSS Evaluated
N/A
NVD
CVE-2026-86115
EUVD
EUVD-2026-71947

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
simstudioai sim 0.8.13
simstudioai sim 0.6.103
simstudioai sim to 0.8.14 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-441 The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.

Attack-Flow Graph

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Executive Summary

This is an Internal Route Confused Deputy vulnerability in the Sim application. It allows authenticated workflow authors to bypass SSRF protections and internal authentication by supplying a URL starting with /api/ in an HTTP block. The system incorrectly classifies these URLs as internal based on a string prefix match without proper scheme normalization, skipping DNS validation and minting an internal authentication token. This token grants access to internal-only endpoints like POST /api/function/execute, bypassing intended security boundaries.

Detection Guidance

Check Sim application logs for requests to internal endpoints like POST /api/function/execute with URLs starting with /api/. Inspect network traffic for internal authentication tokens attached to user-supplied paths. Review code for improper URL prefix matching without scheme normalization in tool routing.

Impact Analysis

If you are an authenticated workflow author, an attacker could exploit this to access internal-only endpoints on the same origin, potentially leading to unauthorized actions or data exposure. The impact is limited to the permissions of the authenticated user since the internal token is minted with their identity. However, it bypasses security controls meant to restrict access to sensitive internal APIs.

Compliance Impact

This vulnerability could lead to unauthorized access to internal endpoints, potentially violating data protection requirements under GDPR or HIPAA. It undermines access controls and segregation of duties, which are critical for compliance. Organizations using affected versions may need to assess exposure and apply mitigations to maintain regulatory compliance.

Mitigation Strategies

Upgrade Sim to version 0.8.14 or later to apply the fix. Disable internal token minting for user-supplied paths. Implement strict URL validation and scheme normalization in tool routing. Review and restrict access to internal endpoints.

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